That cartoon alleges that they would all have to have known the level to which the conspiracy existed, if at all.
It also alleges that all demolition experts involved in said allegation
would have reservations about keeping it a secret (and must be considered alongside the fact that
many heinous conspiracies - which completely undermine what you and I might consider 'common morality' - have been carried out over the centuries. How long was the Tuskegee experiment kept secret? Operation Gladio? What? We are tryin to paint the picture that multi-faceted conspiracies simply 'don't happen' in reality? Is that what you're suggesting? Oh, but wait, this was Nine Eleven! It was the most [insert desired hyperbole here] conspiracy in history and could not (ignoring lack of reference) be kept secret! Contract killers are incapable of keeping such secrets, and first responders are too sharp to be deceived by such a rouse, while in the midst of a senory-overloading situation!
Forgive me if I don't take "well, if it would have been a conspiracy, somebody would have told by now" as a foolproof debunking of the theory. *shrug*
All that being said, though, it
is a cute cartoon.

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